1896.] MICROSCOPICAL JOURNAL. 271 



cess of conjugation restores the waning power of fis- 

 sion. 



15. Stentor. — The "trumpet animalcule" should be 

 examined if obtainable, and compared with Paramaecium 

 and Vorticella. It stands in an intermediate position, 

 having a stem functioning like that of Vorticella but not 

 differentiated from the rest of the body. There is a 

 spiral row of large cilia at the broad end leading to the 

 gullet. Specimens can sometimes be found undergoing 

 transverse fission. 



16. Summary of the Unicellular Animals. — The 

 study of the Protozoa, the branch of the animal kingdom 

 in which these forms are placed, furnishes some data for 

 a general notion of the animal cell. They are all 

 minute masses of protoplasm, having a nucleus, but not 

 having a rigid cell-wall ; they all have powers similar in 

 kind to those of animals at large, which may be stated 

 as: (1) power of feeding and nourishing the body; (2) power 

 of motion and sensation ; (3) power of reproduction. All of 

 these powers are automatic, i. e., they are under the con- 

 trol of the animal. All these animals live in water contain- 

 ing living beings, principally plants, and they have no 

 power to thrive in clear water, that is to say they have no 

 power to make complex chemical compounds such as com- 

 pose the protoplasm of which they are composed, from the 

 simple carbon-dioxyd and ammonia that are to be found 

 in rain-water. 



PART III. — SIMPLE chlorophyll-containing PLANTS. 



17. ProtoCOGCUS is a green growth found on bark of 

 trees and fence-boards in half shaded places. A small 

 particle of it should be mounted in water; gently tapp- 

 ing the cover glass will disperse a number of minute 

 green masses, coloiiies of P.; large single cells should also 

 be studied. Stain a mount with iodine to test for pro- 

 toplasm; how does the green colored material stain? The 



